An electronic device refers to a device that performs a specific function according to an equipped program, such as an electronic scheduler, a portable multimedia reproducer, a mobile communication terminal, a tablet PC, an image/sound device, a desktop/laptop PC, or a vehicular navigation system, as well as a home appliance. For example, such electronic devices may output, as sound or an image, information stored therein or information provided from a communication service provider. As the integration degree of such electronic devices have increased, and super-high speed and large capacity wireless communication has become popular, various functions have recently been equipped in a single electronic device, such as a mobile communication terminal. For example, functions (e.g., an entertainment function (e.g., a game function), a multimedia function (e.g., a music/video reproducing function), a communication and security function for mobile banking, a schedule management function, and an e-wallet function) are integrated into a single electronic device, in addition to a communication function.
Such electronic devices may recognize a user input through various input devices. For example, a power key or side keys can generate an input signal by being mechanically operated by the user, and when a display device is equipped with a touch panel, an input signal can be generated merely by the user's touch. In the structure that generates the input signal merely by the user's touch, for example, recognition accuracy may be adjusted by, for example, setting the software of the touch panel. On the contrary, in the case of the keys, which generate an input signal by being mechanically operated, the accuracy of a key operation may vary depending on, for example, a manufacturing tolerance or an assembly tolerance, and an operating feeling (e.g., a click feeling) to be experienced by the user may also vary. Accordingly, in manufacturing the keys that generate an input signal by being mechanically operated, for example, the manufacturing tolerance or the assembly tolerance may be strictly managed in order to ensure the quality of a predetermined level.